Ecological patterns vary across spatial scales for greater short-horned lizards and ants

Ecological studies tend to focus on patterns and processes at one spatial scale, though substantial variation can exist among populations and among individuals throughout the geographic range of a species. Understanding how organisms vary intraspecifically is a critical component to conserving sensitive species, as the environmental factors that most limit one population may not be the same for another population. One key way in which species vary is in their use of available resources. Species that have specific, narrow resource needs are specialists; these species can be acutely sensitive to environmental changes, as they are likely to be affected by the loss of a particular resource. I used three related studies to understand how spatial variation and spatial pattern could affect conservation of a sensitive species and a threatened ecosystem.;I studied how ecological patterns and processes vary across spatial scales for a dietary specialist, the greater short-horned lizard (Phrynosoma hernandesi), in a sagebrush-steppe ecosystem. I also studied how the spatial dispersion of a key prey species for the lizard, the western harvester ant (Pogonomyrmex occidentalis), affects ecosystem processes in this environment. These ants are ecosystem engineers, altering nutrient composition, water infiltration, and plant diversity around their mounds. Lizards are a particularly sensitive group, with the potential loss of 40% of lizard species worldwide predicted by 2080. The sagebrush-steppe ecosystem is also threatened, and has already declined in area with an increase in extractive energy developments.;Specifically, I asked:;1) What are the ecological consequences of spatial patterns formed by western harvester ant colonies? 2) How do the environmental factors that determine suitable habitat for the greater short-horned lizard vary across spatial scales? 3) How does dietary specialization vary within and across populations of greater short-horned lizards?;I used a combination of field-based research, remote sensing, and mathematical modeling to address these questions.;Western harvester ants maintained robust patterning among colonies, with mounds highly regularly dispersed. The strength of these patterns increased the overall area that ants affected, with implications for community function. My results from the horned lizard studies supported the idea that considering spatial scale is a critical part of conservation research and planning. The environmental factors that determined suitable habitat for horned lizards were inconsistent across spatial scales, and diet specificity varied within and across horned lizard populations. While a single approach to protecting sensitive species may be convenient, populations that differ in their ecological needs require separate management strategies.